In the past, it was recommended that pregnant women keep their heart rate below 140 beats per minute, but those strict guidelines have since been eliminated. Experts now say you don't need to stick to any specific heart rate limits while exercising during pregnancy.
Instead of focusing on the number on a heart rate monitor, know the signs you should look for in your own body. The American College of Obstetricians and Gynocologists (ACOG) recommends that pregnant women get at least 150 minutes of moderate aerobic activity every week. What's considerate a moderate workout? Your heart rate is raised—with no max limit—and you're starting to sweat, but you can still talk normally. As a mom-to-be, you should never exercise so vigorously that you’re out of breath or can’t finish a sentence.
Pushing yourself too hard can decrease blood flow to the uterus or raise your body temperature, which can lead to birth defects. Too much huffing and puffing can also lead to dehydration, which could put you at risk for premature birth. If you’re extremely thirsty, fatigued, have a headache, are dizzy or lightheaded, or have dark-colored pee, chances are you’re dehydrated. Remember that pregnant women typically need between 8 and 12 glasses of water per day, and even more if you’re exercising.